Is Malcolm content to return seafood? (5)
I believe the answer is:
clams
'seafood?' is the definition.
(I've seen this in another clue)
'is malcolm content to return' is the wordplay.
'content' indicates a hidden word (letters contained within the clue).
'to return' says the letters should be written in reverse.
'smalc' is hidden within 'is malcolm'.
'smalc' written backwards gives 'CLAMS'.
(Other definitions for clams that I've seen before include "Their shells are firmly closed" , "Edible bivalve molluscs" , "Marine bivalves" , "Proverbially retentive molluscs" .)